2-PATTERN TEST CAPABILITIES OF AUTONOMOUS TGP CIRCUITS

A method to analyze two-pattern test capabilities of autonomous test p attern generator (TPG) circuits for use in built-in self-testing are d escribed. The TPG circuits considered here include arbitrary autonomou s linear sequential circuits in which outputs are directly fed out fro m delay elements. Based on the transition matrix of a circuit, it is s hown that the number of distinct transitions in a subspace of state va riables can be obtained from rank of the submatrix. The two-pattern te st capabilities of LFSRs, cellular automata, and their fast parallel i mplementation are investigated using the transition coverage as a metr ic. The relationships with dual circuits and reciprocal circuits are a lso mentioned.